Photoluminescence linewidth narrowing of InAs/GaAs self-assembled quantum dots

Abstract

The effects of desorption and diffusion of indium adatoms on the photoluminescence (PL) from InAs self-assembled quantum dots (QDs) are investigated by introducing growth interruptions after QD formation. Large, low-density and small, high-density QDs were grown by molecular beam epitaxy using low (0.01 ML/ s) and high (0.2 ML/ s) growth rates, respectively. The PL from the QDs grown at 0.01 ML/ s and with various growth interruption times exhibit decreasing linewidths from 40 to 32 meV with increasing growth interruption time up to 30 s . The narrowing of the PL linewidth results from improved size homogeneity due to desorption and diffusion of adatoms from small (<30 nm) InAs clusters. The narrowing of the PL linewidth from the InAs dots is combined with low-temperature GaAs capping to obtain a linewidth of 26 meV .